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Observed frequency (%) 120 100 80 60 40 20 0 Sterile lemmas Awn Partition bet. lemma and palea Entire se ed Lemma/ palea only or both Seed part Fig. 16. Observed frequency of Cercospora janseana occurrence on the seed. Fig. 17. Plate cultures of Cercospora janseana (Racib) Const. showing colony growths of PDA, PJA, and VJA incubated at ART, 21 °C, and 28 °C at 15 d after inoculation. Colony characters on culture media (Fig. 17) Colonies on PDA at ART (28–30 °C) grow very slowly and attain a 2.40-cm diam in 17 d. They are azonated, plane to slightly felted, with sinuate margins, slightly radial furrows, and dark gray. The colony appears azonated with radial wrinkles and black on the reverse side of the agar plate. At 21 °C under alternating 12-h NUV light and 12-h darkness, colonies grow very slowly and attain a 2.60-cm diam in 17 d. They are zonated, plane to felted, with sinuate margins and radial furrows, and gray and light gray at the margins. The colony appears azonated with radial wrinkles and black on the reverse side of the agar plate. At 28 °C under alternating 12-h fluorescent light and 12-h darkness, colonies are restricted in growth and attain a 1.4-cm diam in 17 d. They are zonated, felted, with even to sinuate margins and deep radial furrows, and light gray. The colony appears azonated with wrinkles and black on the reverse side of the agar plate. Colonies on prune juice agar (PJA) at ART (28– 30 °C) grow very slowly and attain a 2.40-cm diam in 17 d. They are azonated, plane, powdery to granular with slightly radial furrows and even margins, and dark gray to gray and becoming light at the margins. The colony on the reverse side of the agar plate appears azonated and black. At 21 °C under alternating 12-h NUV light and 12-h darkness, colonies grow slowly and attain a 3.10-cm diam in 17 d. They are slightly zonated, plane, granular, and gray with 0.5- cm white margins. The colony on the reverse side of the agar plate appears azonated and black with orange coloration. At 28 °C under alternating 12-h fluorescent light and 12-h darkness, colonies grow slowly and attain a 3.20-cm diam in 17 d. They are plane, zonated with radial furrows and sinuate margins, and light gray to gray. The colony on the reverse side of the agar plate appears azonated with radial wrinkles and black. Colonies on V-8 juice agar (VJA) at ART (28–30 °C) are restricted in growth and attain a 2.20-cm diam in 17 d. They are zonated, felted, with sinuate margins and deep radial furrows, and light gray to gray with dark gray margins. The colony on the reverse side of the agar plate appears azonated with wrinkles and black. At 21 °C under alternating 12-h NUV light and 12-h darkness, colonies grow very slowly and attain a 2.30-cm diam in 17 d. They are zonated, felted, with even to sinuate margins and deep radial furrows, and light gray to dark gray. The colony on the reverse side of the agar plate appears azonated with wrinkles and black. At 28 °C under alternating 12-h fluorescent light and 12-h darkness, colonies grow very slowly and attain a 2.30-cm diam in 17 d. They are zonated with deep radial furrows and sinuate margins, felted, and brownish gray. The colony on the reverse side of the agar plate is azonated with radial wrinkles and black. 23
Microdochium oryzae (Hashioka & Yokogi) Samuels & Hallett syn. Gerlachia oryzae (Hashioka & Yokogi) W. Gams. Rhychosporium oryzae Hashioka & Yokogi teleomorph: Monographella albescens (Thumen) Parkinson, Sivanesan & C. Booth syn. Metasphaeria albescens Thum. Metasphaeria oryzae-sativae Hara Micronectriella pavgii R.A. Singh Griposphaerella albescens (Thumen) Von Arx Disease caused: leaf scald a. Symptoms Lesions are usually observed on mature leaves. Characteristic symptoms include zonated lesions that start at leaf edges or tips. The lesion shape is more or less oblong with light brown halos measuring 1–5 cm long and 0.5–1 cm wide. Individual lesions enlarge and eventually coalesce. As lesions become old, zonations fade. b. Occurrence/distribution Leaf scald has been reported in all rice-growing countries worldwide (Fig. 18). c. Disease history Leaf scald was first reported in 1955 in Japan, and the causal organism was named as Rhynchosporium oryzae. However, the disease was known under different names. The causal fungus was confused with Fusarium nivale as the anamorph and with Micronectriella nivalis as the teleomorph. Later it was proved that the leaf scald fungus is not F. nivale. The anamorph and teleomorph of the leaf scald fungus have undergone many changes and are now known as Gerlachia oryzae and Monographella albescens, respectively. d. Importance in crop production Leaf scald is very common on rice in tropical Asia. It is considered a relatively minor problem causing little yield loss alone in rice production. Detection on seed a. Incubation period on blotter Using the blotter test, M. oryzae can be observed on rice seeds 7 d after seeding and incubation under NUV light at 21 °C. The detection frequency is about 28.2% on seeds coming from different regions (Fig. 19a,b). b. Habit character Aerial mycelia are absent; light pinkish or light orange to bright orange irregular masses Fig. 18. Occurrence of leaf scald (Ou 1985, Agarwal and Mathur 1988). 24
Page 2 and 3: Contents Foreword Preface v vi INTR
Page 4 and 5: Introduction The purpose of seed he
Page 6 and 7: Functions of seed health testing Se
Page 8 and 9: % infected seed lots 100 80 60 40 2
Page 10 and 11: Table 3. Pathogen profiles closely
Page 12 and 13: Table 4. Germination (%) of untreat
Page 14 and 15: Microorganisms associated with seed
Page 16 and 17: Identification of fungi detected on
Page 18 and 19: Detection frequency (%) 100 80 60 4
Page 20 and 21: moderately fast and attain a 4.32-c
Page 22 and 23: Detection frequency (%) 120 100 Eas
Page 24 and 25: They are feathery to slightly fluff
Page 28 and 29: Frequency level (%) 120 100 East As
Page 30 and 31: a 4.90-cm diam in 5 d. They are eve
Page 32 and 33: Detection frequency (%) 90 80 East
Page 34 and 35: gray, becoming dark near the margin
Page 38 and 39: Sarocladium oryzae (Sawada) W. Gams
Page 40 and 41: a b c e f d f Fig. 35. Habit charac
Page 42 and 43: Fig. 38. Occurrence of black kernel
Page 44 and 45: a b d → → → e → f → f →
Page 46 and 47: d a b e → → → → → f c g h
Page 48 and 49: Fig. 46. Occurrence of minute leaf
Page 50 and 51: of the agar plate appears slightly
Page 52 and 53: Detection frequency (%) 120 100 Eas
Page 54 and 55: Pinatubo oryzae Manandhar & Mew Dis
Page 56 and 57: ange with orange. The pionnotes are
Page 60 and 61: Other fungi detected on rice seeds
Page 62 and 63: a b e c d Fig. 65. Habit character
Page 64 and 65: a d d b c Fig. 69. Habit character
Page 66 and 67: → → → a b f f e d e e c f Fig
Page 68 and 69: a b a Fig. 76. Habit character of F
Page 70 and 71: a b d c d e e Fig. 79. Habit charac
Page 72 and 73: a b c → → → d → Fig. 83. Ha
Page 74 and 75: → → → a b d c Fig. 86. Habit
Page 76 and 77:
a b c Fig. 89. Habit character of P
Page 78 and 79:
a b d c e Fig. 92. Habit character
Page 80 and 81:
→ → → → a b e f → c d Fig
Page 82 and 83:
a b c d Fig. 100. Habit character o
Page 84 and 85:
→ → → → → → a → →
Page 86:
Savary S, Willocquet L, Elazegui FA
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